The invention relates to a balance with a system carrier fixed to the housing and with a balance-scale support part connected by two upper and two lower guide rod struts in the form of a parallel guide to the system carrier, whereby each upper guide rod strut is connected to a lower guide rod strut via two connection areas, which struts are combined to a guide rod plate. The two guide rod plates are fastened laterally to the system carrier and to the balance-scale support part.
A balance of this type is known from U.S. Pat. No. 4,799,561. In this patent, the system carrier and the balance-scale support part are equally wide, so that the guide rod plates which are screwed on laterally are parallel to each other. Moreover, the two guide rod plates are connected to one another in the central area of the guide rod struts via a spacing piece. However, this has the result that in the case of slight differences in the width of a system carrier, balance-scale support part and spacing pieces, the laterally screwed-on guided rod plates are distorted, which impairs the reproducibility of the results. The requirements put on the width tolerances are especially high thereby since the differences in width must be bridged particularly in the critical area of the diminished areas of the guide rods and within a relatively small distance between system carrier and spacing piece and between balance-scale support part and spacing piece. However, this partially cancels out the actual advantage of this design with laterally screwed-on guide rod plates, namely, that only the two guide rod plates determine the quality of the parallel guide and that tolerances part. However, the spacing pieces in the central area of the guide rods can also not simply be omitted, since the stability of the parallel guide vis-a-vis lateral forces on the balance scale becomes too low without them.